Tuners are overrated in the improved mileage department. They will make the lie-o-meter read higher but actually don't usually help much. Some, in fact hurt fuel mileage. I would stay away from anything that plugs into fuel rail pressure sensor and fools the ECM to raising the rail pressure. They are rough on the injectors which already have reliability issues to begin with. I'd recommend a GOOD set of injector nozzles around the 50 hp range to help efficiency and add a little power instead.